Refactor debug/trace ready for Jaeger

debug/trace/memory/memory.go

@@ -1,32 +1,33 @@
-package trace
+package memory
 
 import (
 	"context"
 	"time"
 
 	"github.com/google/uuid"
+	"github.com/micro/go-micro/debug/trace"
 	"github.com/micro/go-micro/util/ring"
 )
 
-type trace struct {
-	opts Options
+type Tracer struct {
+	opts trace.Options
 
 	// ring buffer of traces
 	buffer *ring.Buffer
 }
 
-func (t *trace) Read(opts ...ReadOption) ([]*Span, error) {
-	var options ReadOptions
+func (t *Tracer) Read(opts ...trace.ReadOption) ([]*trace.Span, error) {
+	var options trace.ReadOptions
 	for _, o := range opts {
 		o(&options)
 	}
 
 	sp := t.buffer.Get(t.buffer.Size())
 
-	var spans []*Span
+	var spans []*trace.Span
 
 	for _, span := range sp {
-		val := span.Value.(*Span)
+		val := span.Value.(*trace.Span)
 		// skip if trace id is specified and doesn't match
 		if len(options.Trace) > 0 && val.Trace != options.Trace {
 			continue
@@ -37,8 +38,8 @@ func (t *trace) Read(opts ...ReadOption) ([]*Span, error) {
 	return spans, nil
 }
 
-func (t *trace) Start(ctx context.Context, name string) (context.Context, *Span) {
-	span := &Span{
+func (t *Tracer) Start(ctx context.Context, name string) (context.Context, *trace.Span) {
+	span := &trace.Span{
 		Name:     name,
 		Trace:    uuid.New().String(),
 		Id:       uuid.New().String(),
@@ -51,7 +52,7 @@ func (t *trace) Start(ctx context.Context, name string) (context.Context, *Span)
 		return context.Background(), span
 	}
 
-	s, ok := FromContext(ctx)
+	s, ok := trace.FromContext(ctx)
 	if !ok {
 		return ctx, span
 	}
@@ -65,7 +66,7 @@ func (t *trace) Start(ctx context.Context, name string) (context.Context, *Span)
 	return ctx, span
 }
 
-func (t *trace) Finish(s *Span) error {
+func (t *Tracer) Finish(s *trace.Span) error {
 	// set finished time
 	s.Duration = time.Since(s.Started)
 
@@ -75,13 +76,13 @@ func (t *trace) Finish(s *Span) error {
 	return nil
 }
 
-func NewTrace(opts ...Option) Trace {
-	var options Options
+func NewTracer(opts ...trace.Option) trace.Tracer {
+	var options trace.Options
 	for _, o := range opts {
 		o(&options)
 	}
 
-	return &trace{
+	return &Tracer{
 		opts: options,
 		// the last 64 requests
 		buffer: ring.New(64),

debug/trace/options.go

@@ -1,6 +1,9 @@
 package trace
 
-type Options struct{}
+type Options struct {
+	// Size is the size of ring buffer
+	Size int
+}
 
 type Option func(o *Options)
 
@@ -17,3 +20,15 @@ func ReadTrace(t string) ReadOption {
 		o.Trace = t
 	}
 }
+
+const (
+	// DefaultSize of the buffer
+	DefaultSize = 64
+)
+
+// DefaultOptions returns default options
+func DefaultOptions() Options {
+	return Options{
+		Size: DefaultSize,
+	}
+}

debug/trace/trace.go

@@ -6,8 +6,8 @@ import (
 	"time"
 )
 
-// Trace is an interface for distributed tracing
-type Trace interface {
+// Tracer is an interface for distributed tracing
+type Tracer interface {
 	// Start a trace
 	Start(ctx context.Context, name string) (context.Context, *Span)
 	// Finish the trace
@@ -36,11 +36,6 @@ type Span struct {
 
 type spanKey struct{}
 
-var (
-	// Default tracer
-	DefaultTrace = NewTrace()
-)
-
 // FromContext returns a span from context
 func FromContext(ctx context.Context) (*Span, bool) {
 	s, ok := ctx.Value(spanKey{}).(*Span)
@@ -51,3 +46,25 @@ func FromContext(ctx context.Context) (*Span, bool) {
 func NewContext(ctx context.Context, s *Span) context.Context {
 	return context.WithValue(ctx, spanKey{}, s)
 }
+
+var (
+	DefaultTracer Tracer = new(noop)
+)
+
+type noop struct{}
+
+func (n *noop) Init(...Option) error {
+	return nil
+}
+
+func (n *noop) Start(ctx context.Context, name string) (context.Context, *Span) {
+	return nil, nil
+}
+
+func (n *noop) Finish(*Span) error {
+	return nil
+}
+
+func (n *noop) Read(...ReadOption) ([]*Span, error) {
+	return nil, nil
+}